The present invention relates to an electric hotplate particularly for commercial use in restaurants and the like, with a hotplate body made from cast material and below it heating resistors positioned in substantially spirally arranged slots.
Such hotplates, which are normally referred to as large hotplates, are used in the kitchens of restaurants, canteens, ships, etc. and are subject to increased loading and stressing. They are frequently used uninterrupted for twelve hours and more and are consequently thermally highly stressed and are exposed to increased contamination by spilled or splashed cooking products. They therefore require frequent cleaning, which has hitherto taken place with very violet means and media, e.g. a powerful water jet. Nevertheless a high degree of efficiency, as well as excellent adjustability and controllability are important.
Hitherto large hotplates have been constructed in the same way as domestic hotplates, i.e. with heating resistors in the form of heater coils embedded in an embedding material in slots on the bottom of the cast material hotplate body (cf. e.g. DE-OS (German Offenegungsschrift) 24 22 625).
It is already known to heat electric hotplates with tubular heaters, which are pressed onto the bottom of a disc-like plate, i.e. a plate which is smooth on its underside (DE-OS No. 30 33 828). It is also known from DE-OS No. 25 49 006 to use tubular heaters for heating convection heaters, the tubular heaters being pressed into slots of cast parts. As can be gathered from German Utility Model No. 18 21 380, such devices are also used for heating boilers. However, in that case special measures are taken in order to enclose the tubular heater firmly in the material of the basic body and to press tubular heater into intimate contact therewith. In addition, the slots have a very wide spacing, a uniform heating depending on heat conduction in the basic body.